Real numbers x and y are chosen independently and uniformly at random from the interval (0,1). What is the probability that \left\lfloor\log _{2} x\right\rfloor= \left\lfloor\log _{2} y\right\rfloor, where \lfloor r\rfloor denotes the greatest integer less than or equal to the real number r ?
Answer Choices
A. \dfrac{1}{8}
B. \dfrac{1}{6}
C. \dfrac{1}{4}
D. \dfrac{1}{3}
E. \dfrac{1}{2}